Because that is not what my version of the feat does. Changing Divine Power from 1r/cl to 1m/cl is not a five-fold increase, it's a ten-fold increase.1r/cl-->1m/cl is x10
1m/cl-->10m/cl is x10
But 10m/cl-->1hr/cl is x6
I prefer this because it is simpler to visualize than getting a mathematically correct increased duration.
Also, creating a feat that makes a x3, x4, or x5 duration kind of defeats to purpose of the unstackable nature of metamagic feats in 3.5e. I'd rather just have two feats, Extend Spell and Improved Extend Spell, that cap out at 24 hours. I really don't like the idea of spells lasting for days without some sort of major drawback. (IMC, I lowered deeper darkness and its ilk to 1hr/cl).
ncG1vNJzZmivp6x7prrWqKmlnF6kv6h706GpnpmUqHyntdeipaBloJq%2FtLXSrZynrF2ovaa4y2agpqiipMOmsIyer62dnpl6tLzEpaNncWBlgnd7